#1
After playing through Half-Life2 and then visiting CERN today, I've been ruminating on all that sort of advanced theoretical physics nonsense. Now, typically, I've dropped Physics, and suddenly, I'm finding all that stuff very interesting. So, I had some questions for the bright denizens of the Pit (Oh God, help me ).

Any answers or discussion you can provide on the following topics would be most interesting, whether you're interested in the moral, the scientific, or the socio-economical/political implications of it, or just how fucking awesome they would be.


Teleportation/Portals - Are they possible? I mean, the way I could conceive them working, is a computer scanning the object and analysing its composition, then another one recomposing it, but that would be cloning, and if people tried it, the other person would just be a blank slate, no? So it wouldnt' be teleporting. Or there's the weird one with alternate universes, and slingshotting round them, and whatever the hell goes on in Half-Life. Would they have to be aimed at a receiver, or could you just appear at co-ordinates?

Time Travel I've heard that it's physically impossible, since to do it, you'd need to go faster than the speed of light, and that's not possible for anything with mass. But then is that belief set in stone, or is it one of those things like the earth being flat, etc?


Cheers
#2
Well, the only thing in physics I know for certain is that I like electrons; I'm positive about that.
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#3
Quote by Karvid
Well, the only thing in physics I know for certain is that I like electrons; I'm positive about that.




S t a i r s s r i a t S

#4
Time travel is theoreticaly possible, as time moves slower in low and zero gravity, assuming you could find some form of "worm hole" connecting somewhere with high gravity I.E. earth and somewhere with low gravity I.E. space, you could go through the warm hole on say monday on earth but as time goes slower in space it would be say sunday in space.. theoreticaly of coarse, there are so many problems with this theory though the chances of it ever becoming reality are next to zero... i really am no expert on it though you should read up about it, pretty intresting.
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#6
Quote by gabcd86

Time Travel I've heard that it's physically impossible, since to do it, you'd need to go faster than the speed of light, and that's not possible for anything with mass. But then is that belief set in stone, or is it one of those things like the earth being flat, etc?


Cheers

Its pretty certain that things which have mass can't reach the speed of light, because as you get closer to the speed of light, mass essentially increases, meaning you require a greater and greater force to cause any acceleration, stretching to infinity. It is possible that this could be incorrect, but that would mean undermining a lot of our understanding of physics.
If music was the food of love I'd be a fat romantic slob.
#7
Time travel is possible, at least in to the future, although it's not really true time travel jsut exploiting special relativity. For example if you had a space ship and flew off at 0.99c for a year according to your clock on the ship, a lot longer will have passed on Earth so you'll have effectively travelled into the future.
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#8
The thing is, two thousand years ago no one held flying for possible, or even held humankind remotely capable of doing such thing (let alone the physics we know of nowadays). Therefore I can't see how we wouldn't be able to travel through time in say another thousand years, so yes, I think it is possible.
#12
Quote by Equivalence
The thing is, two thousand years ago no one held flying for possible, or even held humankind remotely capable of doing such thing (let alone the physics we know of nowadays). Therefore I can't see how we wouldn't be able to travel through time in say another thousand years, so yes, I think it is possible.

That's a bad example. People held flying for HUMANS as impossible, but it was possible for other animals very similar to humans. Now we hold time travel as impossible, and it is imposssible as far as things which aren't black holes/tiny particles are concerned. (I don't know if black holes/tiny particles travel through time for sure, I'm just covering my ass against someone saying they do.
If music was the food of love I'd be a fat romantic slob.
#13
When I said time travel, I had in mind more badass applications then going back to yesterday, I must say. This is woefully underwhelming.

Damn you, science!
#14
Quote by Mr_Jubby_Jubs
That's a bad example. People held flying for HUMANS as impossible, but it was possible for other animals very similar to humans. Now we hold time travel as impossible, and it is imposssible as far as things which aren't black holes/tiny particles are concerned. (I don't know if black holes/tiny particles travel through time for sure, I'm just covering my ass against someone saying they do.

I know, bad example. Walking on the moon then, or racing around in magnet trains, whatever, it's about the principle that we human beings have managed to do things that never even occurred to us in the past
#15
Quote by Equivalence
I know, bad example. Walking on the moon then, or racing around in magnet trains, whatever, it's about the principle that we human beings have managed to do things that never even occurred to us in the past

Fair enough, I'm not going to say that we'll never travel through time or teleport, you never know what science will do.
If music was the food of love I'd be a fat romantic slob.
#16
Why not?
Do you really think people believed it possible thousands of years ago to do things such as destroy an entire city with one bomb? Our understanding of Physics changes pretty quickly, and there are still lots of things we know absolutely nothing about. What we know is based off of the properties of matter essentially; something 4.6% percent of the universe is made of. The other 95.4%, we know little to nothing about. As a result, we can't really rule out anything being impossible due to limitations of physics.
#17
Quote by sinan90
Time travel is possible, at least in to the future, although it's not really true time travel jsut exploiting special relativity. For example if you had a space ship and flew off at 0.99c for a year according to your clock on the ship, a lot longer will have passed on Earth so you'll have effectively travelled into the future.

What do you mean "it's not really true time travel"? It is. You travel faster, therefore time slows in your ship and when you step out you're in the future.

To TS:
Your understanding of teleportation in the sense of copying and transmitting data is correct, it is effectively cloning, however time travel and teleportation are inextricably linked in the world of physics in that they could possibly both be realized through manipulation of wormholes in the space time continuum. If we were to create a wormhole entrance in, say, Melbourne, at this precise moment in time, and have the other end of the wormhole set in Toronto in 99 years then travelling through the wormhole would result in you a) travelling through time and b) being teleported. This method of space time travel however depends a) upon bending spacetime, and b) holding a wormhole open for people to travel through. Interesting theory though.

edit:
http://www.amazon.co.uk/Build-Time-Machine-Paul-Davies/dp/0141005343 Buy. Read.
http://en.wikipedia.org/wiki/Spacetime Try desperately to understand.
Last edited by blynd_snyper at Nov 2, 2009,
#18
Quote by gabcd86
After playing through Half-Life 2 and then visiting CERN today, I've been ruminating on all that sort of advanced theoretical physics nonsense. Now, typically, I've dropped Physics, and suddenly, I'm finding all that stuff very interesting. So, I had some questions for the bright denizens of the Pit (Oh God, help me ).

Any answers or discussion you can provide on the following topics would be most interesting, whether you're interested in the moral, the scientific, or the socio-economical/political implications of it, or just how fucking awesome they would be.


Teleportation/Portals - Are they possible? I mean, the way I could conceive them working, is a computer scanning the object and analysing its composition, then another one recomposing it, but that would be cloning, and if people tried it, the other person would just be a blank slate, no? So it wouldnt' be teleporting. Or there's the weird one with alternate universes, and slingshotting round them, and whatever the hell goes on in Half-Life. Would they have to be aimed at a receiver, or could you just appear at co-ordinates?

Time Travel I've heard that it's physically impossible, since to do it, you'd need to go faster than the speed of light, and that's not possible for anything with mass. But then is that belief set in stone, or is it one of those things like the earth being flat, etc?


Cheers




...That's really all I came in to say. I don't know shit about stuff like this.
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#19
#20
Quote by Kapps
Why not?
Do you really think people believed it possible thousands of years ago to do things such as destroy an entire city with one bomb? Our understanding of Physics changes pretty quickly, and there are still lots of things we know absolutely nothing about. What we know is based off of the properties of matter essentially; something 4.6% percent of the universe is made of. The other 95.4%, we know little to nothing about. As a result, we can't really rule out anything being impossible due to limitations of physics.
Those things were inconceivable not because they were theoretically impossible but because there was no theory whatsoever (or little).
Time travel atm defies the laws of physics that have been proven against discreditations and hence aren't dismissable as basically all modern physics would be "wrong" if such things were possible (time travel i mean).

As for teleportation i dont know much but i would guess that, contrary to what someone said, the information would not be limited to matter but it would also be our electrical impulses and so the information would "contain" our memories. again, i don't know much about this but i'd think human teleportation is veeery far away from possible atm
#21
Quote by blynd_snyper
What do you mean "it's not really true time travel"? It is. You travel faster, therefore time slows in your ship and when you step out you're in the future.



Then you could say the same about any journey, heck you travel into the future but just sitting still in a chair. Also time doesn't slow down for the person on the ship, their experience of time is exactly the same as long as they're travelling at constant velocity. It's not time travel in the romantic sense that is often described in science fiction where there is no real passage of time for the traveller but rather an instantaneous journey.
Founder of Jaco society

[22:08:23] <Confusius> I wish I was a bassist
[22:08:26] <Confusius> you fuckers look cool


Want to know how to play bass in jazz? Read this.
#22
Yes teleportation is possible but the technology needed is just too advanced. There was a Horizon program on about a year ago that said if all arrangement of all the atoms in the human body were mapped it would take up roughly 120million megabytes. Even with todays technology the most data we can send down a line is around 50gb/s. So doing the maths, the teleportation would not be instant.
#23
Quote by sinan90
Then you could say the same about any journey, heck you travel into the future but just sitting still in a chair.

Yes, we are.
Also time doesn't slow down for the person on the ship

Yeah it does. The Hafele-Keating experiment proved this to be true through use of atomic clocks
their experience of time is exactly the same as long as they're travelling at constant velocity.
For the majority of time on their journey they will be.
It's not time travel in the romantic sense that is often described in science fiction where there is no real passage of time for the traveller but rather an instantaneous journey.

As v, the velocity of the traveller approaches c, the speed of light, the lorentz factor approaches infinity. ( http://en.wikipedia.org/wiki/Lorentz_factor man I hope you know what that is). Thus the effect of time dilation increases and at very high speeds the journey would appear to be instantaneous. ( http://en.wikipedia.org/wiki/Twin_paradox sorry to keep quoting wiki, but it's a quick easy source).
While this method will not be considered as 'romantic' as travel through wormholes or other such features of spacetime it will produce the same effects.

Out of curiousity what are you studying?
#24
Quote by gabcd86


Time Travel I've heard that it's physically impossible, since to do it, you'd need to go faster than the speed of light, and that's not possible for anything with mass. But then is that belief set in stone, or is it one of those things like the earth being flat, etc?


Cheers



There are no known laws of physics which make time travel an impossibility, this of course does not mean that it is definately a plausible theory. The leading theory in which time travel is poosible at the minute is that if we were able to find a wormhole and enlarge it (which would take a certain substance that I forget the name of, and we arent entirely sure if it exists) we would, with the aid of a machine built for time travel, be able to travel through time. However, we would only be able to travel back in time to the point at which the time machine was created. This therefore disproves Hawkings theory that time travel is impossible because we have yet to see anybody from the future, as all his theory proves is that the time machine has not been successfully built YET.
If your interested, the reason that a wormhole would allow us to travel through time is that time travels slower in areas of high gravity (talking thousands/ millions of times stronger than that which is found on earth). This means that if we travel from our area of low gravity, through the wormhole, to the area of high gravity, we will effectively have gone back in time.

Tl;dr
There are no laws of physics that we are presently aware of which prove that time travel is impossible, but it is unlikely that it is possible.
We'll be washed and buried one day my friend
And the time we were given will be left for the world
The flesh that lived and loved will be eaten by plague
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#25
Quote by blynd_snyper
Yes, we are.


Good. we're agreed.

Yeah it does. The Hafele-Keating experiment proved this to be true through use of atomic clocks


I didn't make it clear what I meant. The person on the ship wouldn't notice their clock ticking more slowly. To them the passage of time is the same. THe ticking is only slower when compared to another clock to which it's moving relative to.

As v, the velocity of the traveller approaches c, the speed of light, the lorentz factor approaches infinity. ( http://en.wikipedia.org/wiki/Lorentz_factor man I hope you know what that is). Thus the effect of time dilation increases and at very high speeds the journey would appear to be instantaneous. ( http://en.wikipedia.org/wiki/Twin_paradox sorry to keep quoting wiki, but it's a quick easy source).
While this method will not be considered as 'romantic' as travel through wormholes or other such features of spacetime it will produce the same effects.


It produces the same results, but it's not what most people will associate with time travel and that's really the point I'm trying to get across.

[qupte]Out of curiousity what are you studying?

Medicine.
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[22:08:23] <Confusius> I wish I was a bassist
[22:08:26] <Confusius> you fuckers look cool


Want to know how to play bass in jazz? Read this.
#26
Quote by sinan90
I didn't make it clear what I meant. The person on the ship wouldn't notice their clock ticking more slowly. To them the passage of time is the same. THe ticking is only slower when compared to another clock to which it's moving relative to.
True, but then again if we're going by the romanticized version of time travel then the person in the machine wouldn't notice the difference until they had reached their destination either, so the function of the machines to all concerned (aside from physicists) is identical.

It produces the same results, but it's not what most people will associate with time travel and that's really the point I'm trying to get across.

Fair enough, I possess a scientific mind, and as such I don't care about associations with science in pop culture, I care about results. If I created a time machine and people complained that it "wasn't what they thought it would be like" you bet they can get fucked 'cos I'm ditching their defenseless arse in the stone age.
#27
Jesus. Now I remember why I dropped physics - it's ****ing complicated - those wikis hurt my brain.